Debates about water in California, the western U.S., and indeed, worldwide, have traditionally focused on the question of how best to further expand water supply to meet some hypothetical future increase in water demand. And the solution frequently offered is to build massive new infrastructure in the form of dams and reservoirs, drill more groundwater wells, or expand water diversions from ever-more-distant rivers, in order to “grow” the supply available for human use.

“Build more traditional water infrastructure” is increasingly the wrong answer to the wrong question.

Except for basic needs like drinking, cooking, and washing, we don’t want to “use” water – we want to grow food, produce semiconductors, generate electricity, and provide other goods and services society demands. These activities and products often require water; but they almost always can be done with less water than we currently spend on them.

The question we should be asking is: how can society satisfy its demands for goods and services with less water – in other words, how can we improve the efficiency and productivity of water use.

And the answer is the potential for improving water-use efficiency is massive, and tapping that potential is far faster, cheaper, and more environmentally sound than new traditional supply infrastructure.

The Pacific Institute has produced a long series of assessments of water-efficiency potential for urban use and agricultural use for California, the Colorado River basin, cities like Atlanta and Las Vegas, and more. That potential is huge, even in regions where water conservation and efficiency efforts have been pursued for many years.

Here is just one clear example, in the California context where arguments about traditional supply versus efficiency improvements continue:

In 1980, almost all toilets in use required around six gallons per flush. In California households, the total amount of water used for toilets in 1980 was around 760,000 acre-feet per year (250 billion gallons per year).

If there had been no change in technology or state and national standards to improve the efficiency of toilets, water usage today for toilets (given population growth, and using estimates for 2010) would be around 1,200,000 acre-feet per year ( around 390 billion gallons per year), a massive increase of more than 440,000 acre-feet of water.

But that’s not what happened.

First California, and then the United States, passed efficiency standards for home appliances, including toilets, showerheads, and washing machines. Today, all toilets sold in the U.S. must use 1.6 gallons per flush or less; all toilets sold in California must be 1.28 gallons per flush or less (and efficient modern toilets are tested and work better than the older models). The Pacific Institute estimates that water used statewide for toilet flushing is now around 550,000 acre-feet per year (180 billion gallons per year).

Because of this single change in water-use efficiency, for a single water-using appliance (albeit an important one), California not only saves more than 640,000 acre-feet (210 billion gallons) of water every year, but we use less water today for toilet flushing than we used in 1980, even though the state’s population has grown by 60 percent.

Toilet efficiency standards alone are already saving California more than 640,000 acre-feet a year compared to 1980 use. And another 290,000+ acre-feet could still be saved if all toilets met the current standards.

But that’s not all. There are still plenty of inefficient toilets out there: If every toilet in the state were as efficient as the current standard, California could reduce total annual water demand by 290,000 more acre-feet (95 billion gallons a year). That is far more water than any new reservoir proposed in the state could generate, at far lower cost. And the newest toilets use even less than the current standards; technology doesn’t stand still.

Figure 1 shows all of these numbers: 1980 use, what 2010 use would have been with no efficiency improvements, actual current use, and additional potential savings.

And even that’s not all. What about washing machines, drip irrigation systems, leak reduction in homes and businesses, improved irrigation, and replacing lawns with low-water-using gardens? All together, the Pacific Institute calculates that existing technology can help meet our demands for water services and yet cut actual annual water demand for cities in California by as much as 2.9 to 5.2 million acre-feet (0.95 to 1.7 trillion gallons a year) – massive additional savings from efficiency improvements. Even more water could be saved in the agricultural sector through efficiency improvements.

Water conservation and efficiency is just one response to California’s extreme drought and longer-term water challenges. But they are the most important pieces, and ones with the greatest potential at the lowest costs. Without previous efforts already made to improve efficient water use, California would be deeply crippled by the drought. Continuing to improve water-use efficiency must be the core strategy for dealing with unavoidable future droughts and our long-term water challenges.

]]>3Peter Gleickhttp://www.pacinst.org/about_us/staff_board/gleick/http://scienceblogs.com/significantfigures/?p=5782015-06-10T20:15:42Z2015-06-10T20:15:42ZIt’s only natural that during a crisis we look to single, “silver bullet” technical solutions, after all, they are supposed to be effective against werewolves, witches, and other monsters. For monsters like the ongoing severe California drought, the current favorite silver bullet is seawater desalination. And why not? California sits at the edge of the largest body of salt water in the world – the Pacific Ocean – and taking salt out of water is a successful, commercial, well-understood technology.

Where does ocean desalination fit into the mix of water solutions for California? And what are the real lessons from Israeli and Australian experiences with desalination?

The real lesson is that desalination is a last resort, and even then, caution is warranted.

Israel didn’t turn to desalination until it radically transformed its agricultural sector to cut production of water-intensive crops like cotton and grains, invested in urban conservation and efficiency far beyond what California (despite its progress) has achieved, and massively expanded wastewater treatment and reuse. And Australia invested $10 billion in desalination plants, four of which they subsequently shut down or derated because they couldn’t afford to run them and didn’t need them.

Water Use: Israel has pursued a very aggressive and effective water conservation program, far exceeding California’s. In Israel, current water use – including for municipal, industrial, and agricultural uses – is around 200 gallons per person per day (gpcd) (around 280 cubic meters per year), a 45% decrease from 1970. California’s water use is currently more than 1,000 gpcd (over 1,400 cubic meters per year), five times larger than Israel’s. Some of this can be attributed to conservation and efficiency, but it also reflects differences in the type and extent of agricultural and industrial development.

The mix of crops in Israel has also shifted dramatically (see Figure 1), away from one dominated by water-intensive, low-valued field crops like cotton, barley, and wheat to one dominated by higher-valued fruits, nuts, and vegetables. California is also moving in this direction, but more slowly.

Irrigation Method: Over 80% of irrigated areas in Israel use micro-irrigation systems and the rest use precision sprinklers or mechanized systems like center pivots. In California, only 38% of irrigated land uses low-volume systems like drip, 15% use sprinklers, and the rest (around 46%) use flood/gravity/other systems (Israel’s Agriculture 2015, CDWR data).

Water Allocations and Rights: In Israel, water is regarded as a national asset protected by law. Users receive an annual quota from the Water Authority. The entire water supply is carefully measured and customers are charged according to their water consumption and the quality of the water used. Recycled water costs about half that of potable water (Israel’s Agriculture 2015).

California allocates water based on a century-old system of water rights; actual water use is not accurately measured or reported, including especially groundwater, and only some water prices are based on volume or quality.

Table 1 summarizes the key differences between Israel’s and California’s water availability and use.

Table 1. Water Comparisons: California and Israel

Water Issue

California

Israel

Total Renewable Water Supply (cubic meters per person per year)

> 2,300

230

Total Water-Use per Person (cubic meters per person per year)

1,400

280

Wastewater Treatment (% of total wastewater)

13%

75%

Total Change in Harvested Agricultural Area (1960 to 2012)

+15%

-14%

Applied Agricultural Water (average), acre-feet per acre

3

1.6

Sources: See full reference list below. Note that one cubic meter is 264 gallons.

And Australia?

Australia’s experience with desalination is equally sobering and enlightening. Australian residents are water misers compared to Californians. Average Australian households uses 54 gallons per person each day (for both indoor and outdoor uses), compared to 230 gallons in California; and in the state of Victoria, water usage is on only 40 gallons per person (Australian Bureau of Statistics 2013).

Australians lowered their water consumption dramatically over the past decade in response to the unprecedented Millennium Drought (2000-2010). Authorities responded by adopting new water-saving habits as well as water-efficient technologies. For example, dual-flush toilets are now found in nine out of ten Australian homes. A third of homes capture rooftop runoff in a rainwater tank, and the government offer rebates to residents installing rainwater tanks or graywater systems to recycle water (Heberger 2011).

The bottom line for desalination in California? There is more desalination in California’s future. But the future isn’t here yet.

California should add desalination to the mix of options only after the state and local agencies do the other things that are more cost effective and environmentally appropriate first: continue to improve the efficiency of current water use, greatly expand wastewater treatment and reuse, and bring our agricultural economy into the 21st century. Even then, local agencies should think twice. There should be no subsidies or accelerated environmental review or special treatment to private companies seeking to build desalination plants and then sell the water under take-or-pay contracts to the public. Either desalination is the right choice or it isn’t. At the moment, in California, it isn’t.

Sources

California Department of Water Resources (CDWR). 2014. Applied Water and Irrigated Acreage from the California Department of Water Resources. Statewide Water Balances, 1998–2010. Sacramento, California.

]]>12Peter Gleickhttp://www.pacinst.org/about_us/staff_board/gleick/http://scienceblogs.com/significantfigures/?p=5732015-05-28T21:09:12Z2015-05-28T21:09:12Z[As part of the Pacific Institute’s ongoing efforts to evaluate the impacts of the California drought and offer strategies, technologies, and policies to reduce those impacts, we are presenting a series of short assessments on “Understanding the Numbers.” This piece is the part of that series.]

California is a wonderful place to grow food. The climate is highly favorable; soils are some of the best in the world, it is located well to serve global distribution markets with major ports and other transportation infrastructure; and normally, some regions are relatively well-watered.

Normally.

In a climate where rainfall is so variable from one year to the next, it makes little sense to talk about what is “normal” but California farmers know to expect that some years will very dry and that sometimes there will be a string of dry years back-to-back.

Media coverage of the current California drought has included various attempts to describe where California’s water goes, from flushing toilets to growing crops to bottled water to supporting fisheries. One high-profile target in the media has been California’s major nut crop – almonds – which has been described (and often vilified) for its water use. Many stories have latched on to an estimate that each almond kernel (nut) requires around a gallon of water to produce.

This Pacific Institute analysis addresses two questions:

Is this number correct?

And if so, what does it really mean?

The Numbers

First, how much water really goes to growing California almonds? The amount of water required to grow any crop varies with the climate, soil, irrigation method, and other factors. To compute the amount of water required, we need to know the acreage of almonds, the amount of water applied per acre, the yield of almonds (measured as the final shelled product) per acre, and the number of almonds per pound. For California, here are the basic numbers:

Acreage of Almonds: In 2014, there were approximately 870,000 acres of almond orchards (bearing) throughout the state, up from around 510,000 acres in 2000 and 770,000 acres in 2010 (USDA 2015). Figure 1 shows the massive expansion of almond, pistachio, and walnut acreage between 2000 and 2014. Total crop acreage in California during this period remained relatively constant due to reductions in plantings of field crops.

Source: USDA 2015

Water Use per Acre of Almonds: All crops require water and the total water requirement varies throughout the growing season as a function of temperature and other climatic factors, the characteristics of the plants themselves, soil conditions, irrigation methods and efficiencies, and more. For almonds, the crop water requirement is roughly between 40 and 55 inches per year – more in the hotter southern California region; less in the cooler northern California areas. Average water use is approximately 44- 48 inches per year (UC Davis; DWR). Certain advanced irrigation methods, such as regulated deficit irrigation, can cut this by as much as 30% or more, but these are not widely applied yet and such methods also may affect crop yields and quality.

Combining these data shows that a pound of almonds requires between 520 to 560 gallons of water:

Nuts per Tree or Weight per Nut: The US Department of Agriculture reports that in California the average number of almonds per tree is around 6,700, and the average weight of each almond kernel (the part we eat) is around 1.4 grams per nut.

Total Water Use for Almonds: Combining these numbers we estimate that total applied water use for almonds in California was around 3.1 million acre-feet in 2010. That number was almost certainly higher in 2014, but no final data for last year are available yet.

Water per Almond: When combined with the yield information above, almonds required between 1.6 and 1.7 gallons of water per nut, somewhat higher than the 1 gallon per nut commonly reported elsewhere, but of a comparable magnitude.

But What Do the Numbers Mean?

Is this a lot of water to produce an almond or a little? How much water does it take to grow a grape, watermelon, head of lettuce, or cow? Is such a measure useful?

It is too simplistic to look at the amount of water required to produce a specific item and pass judgment, without understanding global markets, technology, climate, and more. Farmers make choices of what crops to grow based on many factors and signals, from market prices for commodities, to the quality of their soil, to water availability, to the kinds of equipment in their barns. There is a strong market for almonds and they produce good returns to farmers. In addition, water-use efficiency in almond orchards – that is the amount of water required to produce a particular good or service – has been improving over time as better irrigation technologies and methods have been applied. This is a good thing – it permits growers to produce more food and income per unit water.

But it is also true that the massive expansion of California orchards – especially almonds – imposes some real negative costs to communities, leads to the loss of local groundwater where some wells are drying up, and reduces the flexibility of the State to deal with shortages when permanent crops replace crops that can be temporarily fallowed in bad years. Local opposition to new orchards is growing rapidly and a backlash is likely. A spotlight is being shined on the role of corporate investors in the agricultural sector.

During a severe drought, when there is not enough water to satisfy all demands, tough questions arise: What should California be growing and with what irrigation methods? Should growers with low-priority water rights and uncertain water availability in drought years be able to plant new orchards that require permanent water without bearing all of the risks of those decisions? Should new orchards watered with groundwater be prohibited in regions of severe groundwater overdraft? Should there be a change in water-rights allocations in favor of (or away from) permanent crops? Should specific irrigation methods be required for certain crops or soil types? Should all decisions about water allocations in agriculture be left to economic markets rather than allocated by historical rights, as some economists argue? What role, if any, should public agencies play in influencing or regulating water-use patterns in agriculture? Should the State Water Resources Control Board more explicitly define “reasonable and beneficial use?”

In the end, if the gap between water supply and water demand continues to grow, California will have to make fundamental changes to agriculture in a way that ensures both a strong agricultural sector and a healthy environment. The conversation about how to do this must include a discussion of incentives, disincentives, regulatory and market conditions, and impacts to all affected parties. In the end, it is about far more than just almonds.

]]>8Peter Gleickhttp://www.pacinst.org/about_us/staff_board/gleick/http://scienceblogs.com/significantfigures/?p=5702015-03-17T18:23:26Z2015-03-17T18:23:26ZCalifornia’s hottest and driest drought in recorded history has shifted the sources of electricity with adverse economic and environmental consequences. The Pacific Institute has just completed and released a report that evaluates how diminished river flows have resulted in less hydroelectricity, more expensive electricity from the combustion of natural gas, and increased production of greenhouse gas emissions.

The current severe drought has many negative consequences. One of them that receives little attention is how the drought has fundamentally changed the way our electricity is produced. Under normal conditions, electricity for the state’s millions of users is produced from a blend of sources, with natural gas and hydropower being the top two. Since the drought has reduced the state’s river flows that power hundreds of hydropower stations, natural gas has become a more prominent player in the mix. This is an expensive change.

According to the Institute’s report, between October 2011 and October 2014, California’s ratepayers spent $1.4 billion more for electricity than in average years because of the drought-induced shift from hydropower to natural gas. In an average year, hydropower provides around 18 percent of the electricity needed for agriculture, industry, and homes. Comparatively, in this three-year drought period, hydropower made up less than 12 percent of total California electricity generation. The figure below (Figure 6 from the new study) shows the monthly anomalies in state hydropower generation in wet and dry years, and the severe cuts over the past three years.

The decrease in monthly hydroelectric generation over the past three years can be seen clearly in this figure. Losses in the past three years have totaled 34,000 GWh and $1.4 billion dollars.

A longer view reveals an even more startling economic impact: factoring in the dry years from 2007-2009, the total additional energy cost to the state’s electricity users during the six years of recent drought was $2.4 billion.

This increased reliance on natural gas for the state’s electricity production also has environmental costs. Hydropower has some well-known environmental impacts, especially on rivers and aquatic ecosystems, but it produces few or no air contaminants, whereas burning natural gas emits many pollutants, including climate-changing greenhouse gases. During the 2011- 2014 drought period, burning more natural gas to compensate for limited hydropower led to an eight-percent increase in emissions of carbon dioxide and other pollutants from California power plants.

If the current drought persists, water flowing to drive hydroelectric turbines will continue to shrink and expensive and polluting natural gas will become even more of a factor in the electricity production game.

If there is anything that the past few decades of research and study of major global challenges tells us, it is that truly effective solutions to sustainability challenges require truly integrated approaches across disciplines, fields of study, data sets, and institutions. We are not going to solve 21st century global problems with 20th century tools.

The planet is faced with a wide range of regional and global threats: air and water pollution, loss of biodiversity, a rapidly changing climate and new risks from extreme weather events, energy and food security, conflicts over resources such as water, spread of diseases, and much more. These threats are interconnected, but are typically studied in narrow disciplinary ways.

Now, a new review paper in Science lays out the history and background on the value of integrated systems approaches and the need to consider the Earth to be a large, coupled human and natural system linked “through flows of information, matter, and energy and evolving through time.”

In the past few years, advances in research have developed new influential integrated tools such as environmental footprints, planetary boundary assessments, new “nexus” studies, ecosystem services, and more. Figure 1 shows the global connections associated with movement of “virtual water” in the goods and services traded around the world. This kind of integrated thinking has led to new strategies for reducing risks to societies and environmental resources that had not previously been suggested by more conventional disciplinary, reductionist approaches.

“Virtual” water flows among countries of the world in the form of goods and services traded. This Figure, from the new Science paper, highlights those flows (both imports and exports) in billion cubic meters of water per year.

Among the insights gained by integrated systems analysis is the realization that environmental impacts can be mitigated while simultaneously improving economic efficiency, clarifying environmental responsibilities across political and generational borders, and potentially, reducing in the risk of conflicts over resource constraints.

In short, this new review highlights the value of understanding and managing effects over multiple systems and scales. Academia and our social and governmental management institutions have a long, long way to go before we truly tackle our sustainability challenges in an effective, interdisciplinary way, but as this new paper notes:

“Systems integration for global sustainability is poised for more rapid development, and transformative changes aimed at connecting disciplinary silos are needed to sustain an increasingly telecoupled world.”

2. Tigris and Euphrates River Dams Influence Islamic State Expansion

Conflicts over water have a long history. In 2014, a new analysis described the links between drought, climate change, water management, and the Syrian civil war. By the end of the year, the region’s major dams were targeted for control by the Islamic State (IS) and used as weapons to flood parts of Iraq and to divert water away from some communities for political purposes. IS forces near these dams were also targets of allied air strikes because of the dams’ strategic importance.

3. U.S.–China Climate Agreement Includes Water-Energy Provisions

On November 12, 2014, the President of the United States reached a momentous accord with the President of China to cap greenhouse gas emissions and do a whole lot more for Mother Earth and its human inhabitants. The agreement encourages collaboration between the world’s two largest economies to much more quickly put into place new tools, practices, and especially markets to contend with radically different ecological and economic conditions. The agreement includes two provisions to secure freshwater supplies in energy production. The two nations are 1) investing in research to improve efficiency and conservation in water supply for energy generation and 2) developing a carbon-sequestration demonstration project in China to put to good use the water that is displaced from deep beneath the surface during CO2 storage.

In the year that the U.S. Safe Drinking Water Act turned 40, Toledo, Ohio, Charleston, West Virginia, and towns along North Carolina’s Dan River were the victims of pollution incidents that highlighted the continued challenges in safeguarding water supplies and protecting public health. Toledo shut down its water supply after poisonous algae toxins developed in Lake Erie. Charleston’s water supply was fouled by a chemical spill that prompted the Justice Department to indict the plant’s owners for water-quality violations and obstruction of justice. In North Carolina, a storage basin failure at a Duke Energy power plant sent more than 35,000 metric tons of coal ash, a noxious waste product, flowing into the Dan River, a drinking water source.

The evidence of the links between climate change and extreme hydrologic events grew more powerful in 2014. A series of scientific reports addressed heat waves in Europe, coastal damages in the Eastern United States during extreme tides and storms, flooding in the UK from more intense rain storms, drastic loss of Arctic ice, and droughts in Australia and the Southwestern United States. Lloyd’s of London concluded in May that the influence of rising sea levels increased the damages from Hurricane Sandy by $US 8 billion in New York alone. Sao Paulo, Brazil’s largest city and located close to the water-rich Amazon Basin, suffered its worst drought.

6. America Becomes More Water-Efficient as U.S. Water Use Drops Dramatically

The United States is using less water nationally – according to the U.S. Geological Survey in a report issued in November. The federal science agency found that water use dropped to 355 billion gallons a day in 2010, the lowest level since 1970. California continues to be a leader in efficiency and conservation. It withdrew 38 billion gallons of water per day in 2010, a 17 percent decrease from 2005, and the lowest tally since 1965. The USGS report updates the last national water supply and use survey, which collected data from 2005, when national water use was 410 billion gallons per day. In effect, a nation of 309 million people in 2010 used as much water as 205 million Americans did 45 years ago.

7. China’s South-North Water Transport Canal Opens

China turned the spigot on the central line of its South-North Water Transfer Project, sending the first gush of water from Danjiangkou Reservoir along the 1,432-kilometer route to Beijing and other cities in the country’s dry North. Together with the transfer project’s eastern line, which began operating in December 2013, and a planned western line, the massive diversion will siphon as much as 44.8 billion cubic meters (11.8 trillion gallons) of water each year from the Yangtze River Basin, according to the state-run news agency Xinhua. It is the largest project of its kind in the world, with a price tag upwards of $US 81 billion.

8. Algal Blooms Foul Water Worldwide

Decades of research and billions of dollars spent to understand the causes of toxic algae blooms and oxygen-starved aquatic dead zones around the world have produced more scientific knowledge but achieved few results to solve two of the most dangerous threats to the world’s oceans and fresh water reserves. In fact, according to a growing body of scientific evidence, algae blooms and near-shore ocean dead zones are growing larger and more numerous while endangering important fisheries and drinking water consumed by millions of people.

9. Water-Saving Renewable Energy Technologies Become Mainstream

The Energy Information Administration reported that for the first time solar, wind, and geothermal power sources overtook hydropower in 2014 as the largest sources of renewable electricity in the United States. Wind and solar, which typically require little or no water per unit energy produced, also competed with natural gas as the largest new sources of electrical generating capacity in the United States. Through November, half the new generating capacity came from natural gas while solar and wind accounted for 44 percent, according to the Federal Energy Regulatory Commission. The transition to water-saving renewable energy is accelerating. Less than a decade ago, U.S. hydropower plants accounted for three times as much generation as non-hydro sources. In 2014, said the EIA, wind, solar, and geothermal energy accounted for just over 6.6 percent of U.S. electricity generation and hydropower accounted for just under 6.6 percent. “By 2040,” said the EIA, “nonhydro renewables are projected to provide more than twice as much generation as hydropower.”

10. Water Shutoffs in Detroit Are Factor in Largest U.S. Municipal Bankruptcy

Thousands of residents of Detroit — a city under emergency management that is reeling from decades of deindustrialization and neighborhood decay — were cut off from drinking water supplies last year. Roughly 17,000 residences were shut off between March and August because of overdue bills. Residents pushed back, taking water from fire hydrants to drink, cook, bathe, and flush their toilets, and community leaders organized emergency water deliveries. Meanwhile the accountants, lawyers, and traders collected tens of millions of dollars in fees to complete the largest municipal bankruptcy in U.S. history. The problem in Detroit raised questions about whether the shutoff of water violates the UN-declared human right to water, which requires delivery of a basic amount of water independent of ability to pay.

While we do not know yet what the rest of the wet season will bring – and while we hope for the major storms needed to recharge our rivers, groundwater and reservoirs – it seems increasingly likely that California will not see enough precipitation to get out of the very deep deficit that three years of drought (so far) have produced.

There is, however, some misleading and confusing information out there. Some are already arguing that California’s rainfall is nearly back to normal or that because there may have been more serious droughts in the past we needn’t worry anymore. Most of these claims are based on misunderstandings of California’s hydrology, water systems, or current conditions, and on very narrow definitions of “drought.”

First, to understand the data, it is vital to realize that California’s “water year” runs from October 1 to September 30. This is not the “calendar year” (January to December). This distinction is important, because mixing data from different water years produces inaccurate analyses.

Here is a great example. If we look at the 2014 “calendar” year, it appears that California received a decent amount of water (Figure 1) – still dry, but not abnormally so.

Figure 1. California’s 2014 “calendar year” precipitation seems just slightly dry compared to the past 120 years. But this is a misleading graph. The State’s precipitation is measured by “water year” (Oct-Sept). See Figure 2. (Source: NOAA)

But this is grossly distorted by the heavy rains received in December 2014 – which is actually part of the 2015 water year. If we look at the 2014 water year (October 2013 to September 2014) we can see that last year was critically dry (Figure 2): in fact, only two previous years out of the past 120 were drier (1923-24 and 1976-77).

Figure 2. Precipitation in California’s 2014 “water year” (Oct-Sept) was extraordinarily dry — one of the three driest years in the 120-year record. (Source: NOAA)

Even more appropriate is to look at the past three years of persistent, cumulative drought. And when the last three water years are evaluated (October 1, 2011 to September 30, 2014), we see that the current drought (measured only by precipitation levels) is by far the most severe in the entire instrumental record (Figure 3).

Figure 3: The past three water years (2012 to 2014) are the driest in the entire instrumental record for California.

Second, it is important to understand that “drought” means – from a practical perspective – far more than just “precipitation deficit.” California’s drought is the result of several factors: how much precipitation we receive in rain and snow; how much water is available after taking into account reservoir storage, soil moisture, and groundwater; additional losses of water due to higher than normal temperatures (the past three years have been by far the hottestin California’s record); and the human demand for water. If all of these factors are included, the current drought in California can be considered the worst in recorded history.

And it isn’t over yet.

The current status of the drought – some key indicators.

As noted above, the rains received in December are counted as part of the 2015 “water year” – October 1, 2014 to September 30, 2015. Yet even these rains were not especially heavy. When we put all the data together (and a regular update of these data can be found at the Pacific Institute’s California Drought Update page), here is what we see:

Soil Moisture: One key indicator of the severity of the current drought is a standard measure of soil moisture conditions, called the Palmer Drought Severity Index (PDSI). This index is used to prepare the drought maps published at the US Drought Monitor. As the most recent version shows, the entire state of California is still in severe drought, despite the December rains (Figure 4).

Figure 4: The California Drought Monitor as of January 6, 2015 shows that 100% of the state remains in drought — much of it extreme.

Precipitation: And what did those rains actually do? Not much. As Figures 5 and 6 show, precipitation to date for Northern California is barely at average; and for Southern California it is already below average. Not a great start.

Figure 5: Precipitation to date for Northern California is barely at average, despite the December storms. Far more is needed to fill the current deficit in soil moisture, reservoirs, and snowpack. (Source: DWR)

Figure 6: Precipitation to date for Southern/Central California is already far below average for this date. (Source: DWR)

Reservoir Storage: Even worse, we are starting the water year with critically dry reservoirs. Figure 7 shows the current status of California’s major reservoirs, all of which are remain well below normal even with the storms last month.

Figure 7: California’s reservoirs are still far below normal for this date. Without water in storage, deliveries to farmers and cities will almost certainly be cut back again in 2015 — a classic indicator of drought. (Source: DWR)

Snowpack: Finally, one of the most important measures is how much snow is stored in the mountains. This snow provides water that is used throughout the rest of the year. And as Figure 8 shows, three and a half months into the 2015 water year, California’s snowpack is far below normal. This is very bad.

Figure 8: California snowpack is well below normal for this date. This indicator is particularly important for water supply. (Source: DWR)

California will not dry up and blow away: drought means less water than normal, not zero water. But if the drought continues, increasingly difficult and costly decisions will have to be made, and the ecological, economic, and human impacts will grow. But this is no time to be a Pollyanna – we had better continue to prepare for the worst, since there is no indication that nature will bail us out in the near future.

]]>18Peter Gleickhttp://www.pacinst.org/about_us/staff_board/gleick/http://scienceblogs.com/significantfigures/?p=5502014-12-08T15:57:37Z2014-12-08T15:57:37ZOver the past three years (and indeed, for 10 of the past 14 years) California has experienced a particularly deep drought. How bad is the drought? Is it the worst in the instrumental record? The worst in over a century? The worst in 1200 years? The worst “ever”? And why has it been so bad?

There is no single definition of “drought.” Drought, most simply defined, is the mismatch between (1) the amounts of water nature provides and (2) the amounts of water that humans and the environment demand. As the National Drought Mitigation Center puts it:

“In the most general sense, drought originates from a deficiency of precipitation over an extended period of time — usually a season or more — resulting in a water shortage for some activity, group, or environmental sector. Its impacts result from the interplay between the natural event (less precipitation than expected) and the demand people place on water supply, and human activities can exacerbate the impacts of drought. Because drought cannot be viewed solely as a physical phenomenon, it is usually defined both conceptually and operationally.”

Droughts aren’t a new problem for California. Like any other region of the world, the state is subject to extreme hydrologic events, including both floods and droughts. Long-term climatic data developed from tree-ring reconstructions, other “paleoclimatic” assessments, and the more recent instrumental and satellite records provide a record of extensive and persistent natural droughts going back more than a thousand years.

By any measure, the current California drought is severe, to the degree that Governor Brown made an emergency drought declaration almost a year ago, state and federal water agencies have been forced to greatly cut back deliveries of water to cities and farms from dangerously depleted rivers and reservoirs, and local utilities are asking customers for a mix of voluntary and sometimes mandatory water-use reductions. And the current drought is more severe than in the past in part because of the growth in the state’s population. Today California has 16 million more people than during the severe 1976-77 drought, and nearly 10 million more than during the long 1987-92 drought (Figure 1).

California population from 1900 to 2013. Data from CA Dept. of Finance.

But a new factor must also be acknowledged:

The current California drought is bad because for the first time ever, scientists from many different fields see parallel lines of evidence for the influence of human-induced climate changes, including the fingerprints of higher temperatures and changes in the atmospheric circulation patterns. In short, climate change has made the current drought worse. [A summary of some of the recent peer-reviewed literature is provided at the end of this column for readers wanting to dig deeper.]

There is rapidly growing evidence from a combination of basic climate science, models, and real-world observations that human-caused climate change has influenced and worsened the current drought.[1] Indeed, California is not alone in experiencing the growing impacts of climate change: evidence that climate change is influencing extreme hydrologic events all over the world is now pouring in, from heat waves to coastal damages during extreme tides and storms, flooding from more intense precipitation events, drastic loss of Arctic ice, and droughts.

The rainy season has started again (as of the beginning of the official “water year,” October 1), and there is the hope and chance that California will see an average or even a wet year. But if there is any lesson to be learned from the past few years, it is that California is moving rapidly into a new water regime, where hydrologic extremes, including both droughts and floods, are likely to be both more frequent and increasingly severe, and where the influence of human-induced climate change is ever more apparent.

Even without the new factor of a changing climate, it is time to acknowledge that California is in permanent long-term shortage: even in a “normal” rainfall year more water is now demanded and used than nature provides, leading to growing political conflict, unsustainable groundwater overdraft, and ecological destruction of the state’s rivers, streams, and wetlands. Human-caused climate change just worsens this mix.

Business-as-usual water policies and politics cannot continue. California’s water community must face up to a new reality – a new “normal” – and work to bring our water use back into balance.

**************************************************************

The Science Background (A few recent relevant papers)

“The current California drought is exceptionally severe in the context of at least the last millennium and is driven by reduced though not unprecedented precipitation and record high temperatures.”

“Long-term changes caused by increasing trace gas concentrations are now contributing to a modest signal of soil moisture depletion, mainly over the U.S. Southwest, thereby prolonging the duration and severity of naturally occurring droughts.”

“Although the recent drought may have significant contributions from natural variability, it is notable that hydrological changes in the region over the last 50 years cannot be fully explained by natural variability, and instead show the signature of anthropogenic climate change.”

“Climate change is linked to CA’s drought by two mechanisms: rising temperatures and changing atmospheric patterns conducive to failing rains. The first link is firmly established, and there is considerable and growing body of evidence supporting the second.”

There is growing observational data, physical analysis of possible mechanisms, and model agreement that human-caused climate change is strengthening atmospheric circulation patterns in a way “which implies that the periodic and inevitable droughts California will experience will exhibit more severity…” “there is a traceable anthropogenic warming footprint in the enormous intensity of the anomalous ridge during winter 2013–2014 and the associated drought.”

All models, regardless of their ability to simulate the base-period drought statistics, project significant future increases in drought frequency, severity, and extent over the course of the 21st century under the SRES A1B emissions scenario.

Wehner et al., 2011. Projections of future drought in the continental United States and Mexico. Journal of Hydrometeorology, Vol. 12, December 2011, pp 1359-1377.

“Over the past millennium, late 20th century snowpack reductions are almost unprecedented in magnitude across the northern Rocky Mountains and in their north-south synchrony across the cordillera… the snowpack declines and their synchrony result from unparalleled springtime warming that is due to positive reinforcement of the anthropogenic warming by decadal variability. The increasing role of warming on large-scale snowpack variability and trends foreshadows fundamental impacts on streamflow and water supplies across the western United States.”

[1] None of these studies, and no scientists that I know of, have argued that the drought is “caused” by climate change – that is the wrong question. As I have discussed in an earlier column, the evidence points to the “influence” of climate change worsening these extreme events.

New monthly water use data for California water utilities shows that residential water use varies widely around the state, and that the response to the drought has been uneven. Moreover, in some areas, residential use averages more than 500 gallons per person per day, indicating that we could be doing much more to save water.

In July, the State Water Resources Control Board, or the Water Board, issued an emergency regulation to increase water conservation in urban areas. The new regulations prohibit certain water uses, like washing driveways and sidewalks, and imposed new restrictions on outdoor irrigation. Additionally, water utilities are now required to submit monthly reports on water use, including a comparison to how much water was used during the same month in 2013. Last week, the Water Board published the latest monthly water use reports for 397 urban water utilities. While a handful of utilities failed to report on time, those that did report cover about 99% of the state’s population.

Each water utility reports per-person water use in terms of gallons per-capita per day or “gpcd” and the portion used by residents in and around their homes. The result is a first of its-kind compilation of monthly water use data for urban water utilities in the state. And while officials cautioned that many factors affect water use, these data, displayed on the map below, reveal a number of interesting patterns and trends. Click on a utility’s service area to view a chart of residential water use, and how it compares to the same month last year, and to the average use for the state and its Hydrologic Region.

The Water Board collected information from all of the state’s “urban water suppliers” defined by state law (California Water Code Section 10617) as “a supplier, either publicly or privately owned, providing water for municipal purposes either directly or indirectly to more than 3,000 customers or supplying more than 3,000 acre-feet of water annually.”

We mapped water suppliers using information from the California Department of Public Health’s Drinking Water Systems Geographic Reporting Tool, supplemented by our own research. Where a water supplier serves a large, mostly rural area, we identified populated areas within the service area.

Perhaps the first thing you notice is the vast range in reported water use. Residential water use in September ranged from a low of 45 gpcd in Santa Cruz to a high of 584 gpcd in areas served by the Santa Fe Irrigation District in San Diego County. Water use tends to be lower in the cooler coastal region and in denser, urbanized areas. Likewise, water use tends to be higher in hotter, drier regions and in suburban areas with more outdoor landscaping and lawns. The chart below highlights utilities with the five highest and lowest residential per capita water use rates in the state.

Highest and lowest residential per-capita water use rates among California water utilities in September 2014

The data also show that conservation efforts have been extremely uneven around the state. In January, Governor Jerry Brown declared a state of emergency and called on Californians to reduce their water usage by 20 percent. To date, conservation efforts have fallen short of the governor’s target, despite the fact that a majority of Californians believe that there is a “serious water shortage.” Water use in September 2014 was down an average of 10% compared to the previous year. In fact, only 40 out of 397 water utilities reported water use reductions of 20% or more. Cities that saw the biggest cuts in water use include Bay Area cities of Dublin, Livermore, Menlo Park, and Pleasanton, Santa Cruz on the Central Coast, as well as the Southern California cities of Santa Barbara and Santa Maria. For a handful of water utilities, water use actually increased in the past year, despite the drought. Cities that saw water use creep up include East Palo Alto, Crescent City, Gilroy, Lodi, Newport Beach, and Sonoma.

And while Californians have made gains in using water more efficiently in the last few decades, these recent data shows that there is still plenty of room for improvement. Statewide, residential water use in September averaged 125 gpcd. A recent analysis by the Pacific Institute showed that an average Californian living in a home equipped with widely-available water-efficient appliances and fixtures would use about 32 gallons per day indoors. In addition, many Californians could reduce their outdoor water use by 70% or more by landscaping with low water-use plants. International experience demonstrates that such dramatic savings are possible. For example, Australian households use an average of 54 gpcd for both indoor and outdoor uses, and residents of the Australian state of Victoria use only 40 gpcd.

The Aussies weren’t always water misers, but decreased their water use dramatically in response to a decade of drought. Similar changes are underway in California, but should be accelerated. For example, turf removal or “cash for grass” programs are enjoying huge popularity around the state. Replacing lawns with California natives or Mediterranean plants has a host of benefits beyond water savings: colorful blooms that attract birds and pollinators; ease of maintenance; and less need for fertilizers and pesticides. Other efficiency improvements are also possible, e.g., finding and repairing leaks and upgrading toilets, clothes washers, faucets, and showerheads to water-efficient models with a WaterSense or Energy Star label.

We will continue to monitor the latest data from the Water Board to gage drought response around the state and look for interesting trends and new ways to visualize and understand these data. What do you notice when you look at these numbers?

]]>3Peter Gleickhttp://www.pacinst.org/about_us/staff_board/gleick/http://scienceblogs.com/significantfigures/?p=5432014-11-05T17:37:06Z2014-11-05T17:37:06ZThe most important trend in the use of water is the slowly unfolding story of peak water in the United States and elsewhere. Data on US water use are compiled every five years by the US Geological Survey, covering every state and every sector of the economy. The latest data – for 2010 – have just been released, and they show the continuation and acceleration of a stunning trend: US water withdrawals, for all purposes, are declining, not growing.

Traditional water planning and management assume inevitable, continuing, lockstep growth in demand for water as populations and economies expand. This has led to calls for continued expansion in traditional water infrastructure: dams, aqueducts, groundwater extraction, and long-distance water transfers.

But over the past 40+ years, this assumption has been proven false. (See previous commentaries on this, here and here.) New limits on water availability, the changing nature of our economy, new technologies that permit great improvements in efficiency and productivity of water use, and new management approaches have broken the two curves of water use and traditional population and economic growth apart.

In short, the US has reached the era of peak water.

Below are two graphical representations of this remarkable change from the Pacific Institute using data on the US economy together with the USGS water use estimates. The first shows total gross domestic product of the US from 1900 to 2010 (in inflation-adjusted 2005 dollars) together with total “withdrawals” of water for all purposes – from domestic and industrial use to irrigation and power plant cooling. As shown, the most recent water withdrawals data show that withdrawals in 2010 were lower than at any time in the past 40 years back to 1970.

US GDP in $2005; Water Withdrawals in cubic kilometers per year. Data from USGS and USBEA.

The second graph shows the “economic productivity” of water use, measured by the 2005 dollars of gross domestic product generated with every 100 gallons of water withdrawn. This productivity of water use has tripled since 1970 and we now get over $10 of GDP for every 100 gallons of water withdrawn. (Again, these data are adjusted for inflation.)

$2005 of GDP produced for every 100 gallons of water withdrawn in the US. Data from USGS and USBEA.

The assumption that demand for water must inevitably grow is false. Let’s start planning for the reality that a healthy economy and population can mean more sustainable, efficient, and equitable water use.

USGS 2010 Water Use Data: Maupin, M.A., Kenny, J.F., Hutson, S.S., Lovelace, J.K., Barber, N.L., and Linsey, K.S., 2014, Estimated use of water in the United States in 2010: U.S. Geological Survey Circular 1405, 56 p., http://dx.doi.org/10.3133/cir1405.